To see your brother in your dream symbolises some aspect of your relationship with him. It can also serve to remind you that someone in your waking life has certain characteristics or behaviors similar to your brother.
If you do not have a brother and dream that you have one, then he may symbolise characteristics that you need to acknowledge within yourself. The brother in your dream can also be synonymous with a close friend or buddy. Brother also has religious implications and thus represents spiritual issues. Consider also the familiar phrase “big brother is watching you” which indicate that your dream has to deal with issues of authority and oppression.